1631915261 has 2 divisors, whose sum is σ = 1631915262. Its totient is φ = 1631915260.

The previous prime is 1631915227. The next prime is 1631915267. The reversal of 1631915261 is 1625191361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1289887225 + 342028036 = 35915^2 + 18494^2 .

It is an emirp because it is prime and its reverse (1625191361) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1631915261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1631915267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 815957630 + 815957631.

It is an arithmetic number, because the mean of its divisors is an integer number (815957631).

Almost surely, 2^1631915261 is an apocalyptic number.

It is an amenable number.

1631915261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1631915261 is an equidigital number, since it uses as much as digits as its factorization.

1631915261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 35.

The square root of 1631915261 is about 40396.9709384256. The cubic root of 1631915261 is about 1177.3326856299.

The spelling of 1631915261 in words is "one billion, six hundred thirty-one million, nine hundred fifteen thousand, two hundred sixty-one".